WO2012083585A1

WO2012083585A1 - Well logging device, well logging method and data processing apparatus

Info

Publication number: WO2012083585A1
Application number: PCT/CN2011/002099
Authority: WO
Inventors: 杨锦舟; 李作会; 林楠; 魏宝君; 刘庆龙; 肖红兵
Original assignee: 中国石油化工股份有限公司; 中国石化集团胜利石油管理局钻井工艺研究院
Priority date: 2010-12-23
Filing date: 2011-12-14
Publication date: 2012-06-28
Also published as: NO20131015A1; JP2014503819A; US9377555B2; CA2822506C; NO346394B1; GB201311636D0; CA2822506A1; CA2992897C; JP5944923B2; CN102628357B; US20130338925A1; GB2500156B; US20160274265A1; GB2500156A; CN102628357A; GB201612390D0; GB2536837A; CN102628358B; CN102628359A; CN102628359B

Abstract

A well logging device, a well logging method and a data processing apparatus therefor are provided. The well logging device comprises a drill collar body and an antenna array. The antenna array comprises at least one pair of transmitting antenna and receiving antenna, and the transmitting antenna and the receiving antenna are used for generating a forward detection depth curve. By use of the well logging method, not only can the change of the forward stratum resistivity of the well drilling be measured in real time in a well drilling process, but also characteristics of different resistivity stratum interfaces in the forward direction can be distinguished in the drillingprocess.

Description

Logging device, logging method and data processing device

The present invention relates to the field of logging technology, and more particularly, the present invention relates to the field of drilling while drilling technology, and in particular, the invention relates to a logging device, a logging method and a corresponding method for geosteering in a drilling engineering. Data processing equipment. Background technique

At present, in the field of measurement while drilling in oil and gas exploration, coalbed methane, shale gas captured in shale formations, coal mining, etc., formation resistivity is often used to form stratigraphic profiles and determine reservoir oil saturation. Degree, gas content of coal structure and mineral faults, so formation resistivity is the main basis for logging interpretation and evaluation of oil and gas, coal and mineral storage. Known drilling-while-drilling resistivity logging techniques include LWD lateral resistivity logging, LWD electromagnetic transmission resistivity logging, and LWD induction resistivity logging.

The working principle of the lateral resistivity logging device while drilling is mainly to provide current by the power supply electrode, form an electric field in the formation around the wellbore, measure the distribution of the electric field in the formation, and obtain the formation resistivity. The while-drilling lateral resistivity logging device uses the drill bit itself as an electrode. It is also possible to use a ring electrode and three button electrodes close to the drill bit for resistivity measurement. With the drill bit as the electrode, the LWD lateral resistivity logging device can measure the resistivity of a 5-10 cm thin layer before the mud intrusion or the wellbore may be damaged. With three button electrode arrays, high-resolution lateral resistivity measurements can be made to reduce the effects of surrounding rock and provide true resistivity response even in salt grout or high resistivity formations. In addition, if a ring electrode is applied, resistivity information in the 360° range around the wellbore can be obtained.

However, the LWD lateral logging resisting device has the following disadvantages: Because the lateral resistivity logging is a DC logging, the first step is to have a supply electrode to direct the DC current into the formation, and then use a measuring electrode to measure a point in the well. The potential, so this lateral resistivity logging method can only be used when there is conductive mud in the well to provide a current path. However, during actual drilling operations, such as during oil drilling, sometimes oil-based mud drilling is required to obtain the original oil saturation information of the formation, even using air drilling. Under such conditions, direct current measurement cannot be used. Wells, ie, while drilling lateral resistivity logging methods, are no longer applicable in these situations.

The electromagnetic wave propagation resistivity logging device while drilling uses a multi-wire tether design with a propagation frequency of 1 ~ 8MHz, the coil is based on the body structure of the drill collar, and the coil system is wound on the drill collar. By measuring the amplitude ratio or phase difference between the different source distances of the receiving line, and then converting to the apparent resistivity of the formation, the phase shift is measured shallow. Resistivity and attenuation of deep resistivity. Ideally, the longitudinal resolution of the electromagnetic wave propagation resistivity logging device is determined by the spacing of the two receiving coils. The measurement data of the multiple detection depths can be used to explain the intrusion condition. It is generally considered that the phase resistivity is shallow. The decay resistivity has a large depth of detection.

The publication entitled CN101609169A, entitled "A Method for Improving the Measurement Accuracy of Electromagnetic Wave Resistivity and Extending the Measurement Range" discloses the calculation of the mutual inductance electromotive force between the transmitting antenna and the receiving antenna, eliminating the amplitude attenuation of the mutual inductance electromotive force. A resistivity conversion diagram and a phase difference-resistivity conversion diagram are the mutual inductance electromotive force, the circuit zero signal, and the antenna system base value signal independent of the formation resistivity, and the phase difference and the amplitude attenuation are converted to the formation resistivity.

In addition, the paper published in the Journal of China University of Petroleum, "The basic principle of the electromagnetic coil resistivity measuring instrument for tilting coils while drilling and its application in geosteering" uses the magnetic dipole source of the anisotropic horizontal layered medium to calculate the tilt The response of the coil electromagnetic wave resistivity measuring instrument while drilling, analyzing the influence of the relative inclination angle of the wellbore and the inclination angle of the receiving line on the amplitude ratio and phase difference of the received signal, and the peak of the response curve of the conventional instrument and the new instrument in the direction perpendicular to the instrument axis The nature of the formation, thus predicting the existence of stratigraphic boundaries earlier.

However, although various existing electromagnetic wave propagation resistivity logging devices capable of measuring electromagnetic wave resistance resistivity can measure resistivity of different detection depths, the existing various electromagnetic wave propagation resistivity logging devices while drilling have the following disadvantages: First, while drilling The electromagnetic wave propagation resistivity logging device uses a signal frequency that is too high, and its detection depth is limited due to the electromagnetic wave propagation effect. Secondly, the measurement results of the electromagnetic wave propagation resistivity logging device while drilling will be affected by geological factors, especially the surrounding rock, because the measurement results of the device are not limited to the formation area between the receiving coils, and the transmitting coil to the receiving The entire formation parameter between the turns is related, even the formation in a smaller area around the launch line will have an impact on the measurement results, so the vertical resolution of the logging device depends to a large extent on the entire device. The resistivity of the formation. Third, since the wire-wound system of the electromagnetic wave-transmitting resistivity logging device is wound around the surface of the drill collar, the manufacturing process is very complicated, and the coil system is extremely susceptible to wear and damage during use, and when the well is drilled When the size changes, the coil needs to be re-rolled, and the maintenance inspection is complicated and the maintenance cost is high. In addition, similar to the lateral resistivity logging device while drilling, the electromagnetic wave propagation resistivity logging device cannot be operated in oil-based mud. The on-board induction resistivity logging device utilizes the principle of electromagnetic induction. When an alternating current of constant amplitude and frequency is applied to the emission line, an eddy current is induced in the surrounding formation of the coil, and the eddy current itself forms a secondary alternating electromagnetic field. Under the action of the secondary alternating electromagnetic field, an induced electromotive force is generated in the receiving coil. The magnitude of the electromotive force is related to the conductivity of the formation. The formation resistivity can be obtained by measuring the induced electromotive force.

At present, the coil of the induction-resistance resistivity logging device adopts one transmitting coil and two receiving coils, one of the two receiving coils is a main receiving coil, and the other is a compensating coil, and the coil is placed on the drill. In the V-shaped groove with the reflective layer on the side, the logging response is sensitive to the resistivity change of the formation in the front area of the V-shaped groove, and therefore has the characteristics of directional measurement. The while-drilling resistivity logging device is powered by a battery, and a male snap connector is attached to the top of the battery. The male snap connector can be connected to the female snap connector at the bottom of the LWD logging device for The LWD inductive resistivity logging device delivers real-time data, and the same sensor sub-section can be used for different sizes of wellbore requirements.

The advantages of this MWD logging device are: The signal frequency is 20 kHz, which is much lower than the frequency of the high frequency device, so it is not easily absorbed by the formation. The depth of detection is deep and the measurement range is large, which can reach 0.1-1000 ohms. M, and its structural design is simple, a sensor sub-section can be applied to the needs of different sizes of wells, maintenance inspection is simple, and different types of drilling fluids are applicable.

However, such a Drilling Induction Resistivity Logging Device has the following disadvantages: Since the device employs a coil system consisting of one transmitting coil and two receiving turns with a single fixed depth of detection, the logging device can only Providing a formation resistivity with a radial depth of investigation cannot be used to explain complex intrusion profiles and to divide the permeable layer. In addition, for the permeable layer, the mud intrusion causes the resistivity to change radially. Since only one radial detection depth resistivity value can be obtained at the same depth point, the LWD induction logging device cannot be used. Explain the situation of stratum intrusion, it is impossible to determine the situation of reservoir intrusion by mud and reservoir permeability, which is not conducive to the interpretation of oil and gas layers, and thus cannot be used to accurately measure the true resistivity of the formation. In addition, for different types of mud intrusion and resistivity of different radial depths, the characteristics of the oil and gas layers are different. According to the different degrees of different depths, the resistivity curve is affected by the mud intrusion, and the oil and gas The difference characteristics exhibited in the layer can identify oil and gas, so multi-depth resistivity measurement is very important for the logging while drilling device. However, the current Drilling Induction Resistivity Logging Device cannot meet this requirement. Because its coil system design structure is fixed, each type of wire can only provide one depth of electricity. Resistivity, to obtain resistivity at different depths of detection, it is difficult to achieve multiple times with different coil systems. ^ ^: ' ^ ^

In summary, no matter which of the above-mentioned while-resistance resistivity logging devices, there are many defects, and the above-mentioned various LWD resistivity logging devices are only devoted to the method research and calculation of the radial depth of detection. There is no mention or involvement in forward detection depth. However, as the number of transmitting and receiving antennas of various types of LWD logging devices continues to increase, the transmission frequency decreases, and forward depth detection becomes more and more important for drilling engineering. Therefore, drilling is currently underway. The need for a forward-while-drilling method in the logging field is becoming more and more urgent. SUMMARY OF THE INVENTION: The present invention provides a new logging while drilling method, which can not only measure the forward resistivity change of the well in real time during the drilling process, but also distinguish different resistivity layers in front of the drilling process. Interface features.

According to an aspect of the invention, a logging method is provided, comprising:

(a) a homogeneous measurement point selection step in which the logging device selects two consecutive measurement points for at least two consecutive measurements;

(b) determining, based on the measurements at the two consecutive measurement points, whether the selected two consecutive measurement points are capable of being a homogeneous formation selectable point; if so,

(c) determining, according to the two selected points of the homogeneous formation, an amplitude ratio base value and a phase difference base value of the sensing signal of the logging device corresponding to the formation resistivity of the measured high resistance target layer;

(d) determining, according to the amplitude ratio base value and the phase difference base value, a magnitude ratio standard value and a phase difference standard value corresponding to the measured resistivity of the layer;

(e) setting an exit threshold of the measured high resistance target layer according to the amplitude ratio standard value and the phase difference standard value;

(f) continue to select the next measurement point for at least two measurements;

(g) determining whether the sense of the amplitude of the electromotive force and/or the amount of change in the phase difference between the pair of receiving coils of the logging device at the current measuring point is greater than the threshold of the exiting layer;

(h) If the result of the determination in step (g) is YES, it is determined that a low-resistance formation appears in front of the logging device. According to another aspect of the present invention, a data processing device is provided, characterized in that the data processing device comprises:

The homogeneous formation optional point determining device (1403, 1404) is used for determining whether two consecutive measuring points currently selected by the logging device can be used as the selective points of the homogeneous formation;

a base value determining device (1406) for determining, based on the two selectable points of the homogeneous formation layer, if the determination result of the homogeneous formation point selectable device (1403, 1404) is YES The amplitude of the induced signal of the logging device corresponding to the formation resistivity of the measured high resistance target layer is greater than the base value and the phase difference base value;

a standard value determining device (1407) for determining an amplitude ratio standard value and a phase difference standard value corresponding to a formation resistivity of the measured high resistance target layer according to the amplitude ratio base value and the phase difference base value;

a layer threshold setting device (1408) configured to set an exit threshold of the measured high resistance target layer according to the amplitude ratio standard value and a phase difference standard value;

a third-th nth measuring point selection and calculating device (1409) for continuously selecting the next measuring point for at least two measurements, and calculating a pair of receiving coils of the logging device at the currently selected measuring point The magnitude of the induced electromotive force between the amount of change and the amount of change in phase difference;

a low-resistance formation determining device (1410), comprising an out-of-layer threshold determining unit (14101), configured to determine whether an amplitude ratio change amount and/or a phase difference change amount at the currently selected measurement point is greater than The exit threshold; if so, it is determined that a low-resistance formation is present in front of the logging device.

According to still another aspect of the present invention, there is provided a logging apparatus, characterized in that the logging apparatus comprises a drill collar body (12) and an antenna array, wherein the antenna array comprises at least one pair of transmitting antennas and receiving antennas, The transmit and receive antennas are used to generate a forward detected depth profile.

Compared to radial depth detection, the forward depth detection according to the present invention has the following important significance: First, the forward depth detection according to the present invention can effectively control the trajectory of the drilling engineering slant section; the well-known horizontal section measurement formation usually The horizontal layered distribution is assumed first. When the slanting is started, the resistivity logging device is nearly perpendicular to the horizontal layered strata, so the radial detection response can only reflect the change of the resistivity of the measured formation at a certain level. The response to the probe has multiple forward detection depths, which reflect the change in resistivity of the measured formation at different depths of the well, which can effectively identify the layer boundary and the oil-water contact, and adjust the oblique curvature. Make it accurate and smooth, and thus ensure the quality of drilling in the inclined section. Secondly, when the drilling enters a complex high-angle well or horizontal well section, the forward depth detection according to the present invention can perform forward detection of different depths on the front end of the drilling well, which is more direct and accurate than the radial detection method. Pre-determine thin oil layers, complex folds and mutual interlayers, so as to effectively bypass the faults and drill long distances along the high dip reservoir to obtain the highest oil and gas effective drilling rate.

The logging method and the corresponding data processing device according to the present invention can measure the change characteristics of the resistivity change rate of the formation in real time during the drilling process, and accurately resolve the formation interface and the oil-water interface in real time, and capture the optimal timing of entering the oil and gas reservoir. In the high-level dip angle and the anisotropic formation horizontal well, the geological information in front of the drill bit can be predicted for a long distance and the well trajectory can be adjusted in time to control the drilling tool to travel through the optimal position of the reservoir, so as to obtain the maximum oil-touch surface, which is very suitable for Geosteering in petroleum engineering. BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1 shows a logging device in accordance with a preferred embodiment of the present invention;

Figure 2 is a diagram showing a two-layer formation model used in the logging method according to the present invention; Figure 3 is a graph showing the relationship between the amplitude attenuation response of the formation and the position of the formation interface with a resistivity contrast of 10/1;

Figure 4 shows the relationship between the displacement response of the formation with the resistivity contrast of 10/1 and the position of the formation interface;

Figure 5 shows the relationship between the amplitude attenuation response of the formation with a resistivity contrast of 50/1 and the position of the formation interface;

Figure 6 shows the relationship between the displacement response of the formation with the resistivity contrast of 50/1 and the position of the formation interface;

Figure 7 is a graph showing the relationship between the amplitude attenuation response of the formation and the position of the formation interface with a resistivity contrast of 200/1;

Figure 8 is a graph showing the relationship between the displacement response of the formation and the position of the formation interface with the resistivity contrast of 200/1;

9 is a comparison table of various measured formation resistivity and amplitude ratios and phase difference eigenvalues of the antenna system T2-R1 - R2 in the logging device according to a preferred embodiment of the present invention at a transmission frequency of 2 MHz. ;

Figure 10 illustrates various measured formation resistivity and amplitude ratios of antenna systems T2-R1 - R2 in a logging device in accordance with a preferred embodiment of the present invention at an emission frequency of 400 kHz. a comparison table of eigenvalues of phase differences;

Figure 1 1 shows a comparison of various measured formation resistivity versus amplitude ratios and eigenvalues of phase differences for antenna systems T1 - R1 - R2 in a logging device in accordance with a preferred embodiment of the present invention at a transmission frequency of 2 MHz. Table

Figure 12 is a table showing the measured values of formation resistivity versus amplitude ratio and phase difference of the antenna system T1 - R1 - R2 in the logging device in accordance with a preferred embodiment of the present invention at an emission frequency of 400 kHz. ;

detailed description:

Certain terms are used throughout this document to indicate specific system components. As will be recognized by those skilled in the art, the same components may be denoted by different names, and thus the present application is not intended to distinguish between components that differ only in name but not in function. In this application, the terms "comprise", ", "include" and "have" are used in an open form, and therefore should be interpreted to mean "including but not limited to: In addition, the terms "substantially", "substantially" or "approximately" as used herein may relate to tolerances accepted by the industry for the corresponding term. The term "coupling" as may be used herein includes Direct coupling and indirect coupling via additional components, components, circuits, or modules, where indirect coupling, components, components, circuits, or modules do not alter signal information but can adjust their current levels, voltages Horizontal, and/or power levels. Inferred coupling (eg, one element is inferred to another element by inference) includes direct and indirect coupling between two elements in the same manner as "coupling."

In the following description, numerous specific details are set forth However, it will be apparent to those skilled in the art that the device, method and apparatus of the present invention may be practiced without these specific details. References to "invention", "example" or similar language in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example, but not It must be included in other embodiments or examples. The wording in different positions in this specification is "in one embodiment", "in a preferred implementation The examples, or the like, are not necessarily all referring to the same embodiment.

The invention is further described below in conjunction with the preferred embodiments and the drawings.

1 shows a logging device, an electromagnetic wave propagation resistivity detecting device, comprising a drill collar body 12, an antenna array 7-1 1 , 13-15, an internal electronic circuit (in the figure) according to a preferred embodiment of the present invention. Not shown) and a cured seal for coupling the components.

As shown in Fig. 1, the drill collar body 12 is preferably made of a stainless steel material having a cylindrical shape and an axial through hole in the present embodiment, and the outer surface of the drill collar body 12 is preferably engraved with a large amount. Preferably, a ring or an elliptical groove is used to mount the transmitting or receiving antenna.

In the preferred embodiment illustrated in Figure 1, the antenna array comprises four transmit antennas T1 (as indicated by reference numeral 1), T2 (as indicated by reference numeral 14), and T3 (as indicated by reference numeral 13). Show) and T4 (as indicated by reference numeral 15), and 4 receiving antennas R1 (as indicated by reference numeral 7), R2 (as indicated by reference numeral 8), R3 (as indicated by reference numeral 9) ) and R4 (as indicated by reference numeral 10).

As shown in FIG. 1, the order of arrangement of the transmitting antenna and the receiving antenna from the left side of FIG. 1 to the right side of FIG. 1 (ie, from the tail end of the drill collar body 12 to the drill bit end) is preferably: receiving antenna R3, A transmitting antenna T3, a transmitting antenna T1, a receiving antenna R1, a receiving antenna R2, a transmitting antenna T2, a transmitting antenna Τ4, and a receiving antenna R4. In the preferred embodiment, the midpoint between the receiving antennas R1 and R2 is a measuring point, and the transmitting antennas T1, Τ2, Τ3 and Τ4 are preferably symmetrically mounted around the measuring point, respectively. The receiving antennas R1 and R2 are preferably receiving antenna pairs with a mounting angle of zero, and the receiving antennas R3 and R4 are another pair of receiving antennas with the measuring point as a center of symmetry, as shown in FIG. R3 and R4 are preferably located at both ends of the drill collar. The mounting angles of the receiving antennas R3 and R4 can be arbitrarily set, and in the present embodiment, they are preferably, but not limited to, set to 45° and -45°.

For any one of the transmitting antennas and a pair of receiving antennas (for example, the transmitting antenna T1 and the receiving antennas R1 and R2), when the transmitting antenna is excited, the electromagnetic signal propagates through the surrounding ground and the drill collar body, and is reflected and transmitted through the ground layer. An electromagnetic induction signal is generated on the receiving antenna, and the electromagnetic induction signal is collected by the receiving antenna, then subjected to signal processing such as amplification and filtering via the internal electronic circuit, and finally converted into a function of the resistivity of the propagating formation. When the logging device (in this embodiment, the electromagnetic wave propagation resistivity detecting device) is operated downhole, if the formation electrical parameters (such as formation resistivity contrast) in front of the device are unchanged, it means that no layer boundary appears. , the electricity reflected to the receiving antenna at this time The magnetic signal will not change, and if the electrical parameters of the formation in front of the device change, it means that a layer boundary appears, and the electromagnetic signal reflected to the receiving antenna will change, resulting in a signal difference, constantly This signal difference is calculated and calculated, and the distance of forward detection can be obtained.

A combination of any of the transmitting antennas and any of the sets of receiving antennas in the logging device (in this embodiment, the electromagnetic wave propagation resistivity detecting device) can generate a forward detecting curve through all of the front Comparing and processing the detection curve can eliminate environmental influences (such as wellbore effects) and measurement errors, thereby improving the forward detection accuracy of the logging device.

Hereinafter, a specific logging while drilling method according to another preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 13, a logging method according to a preferred embodiment of the present invention - a method for forward detection of electromagnetic wave resistivity, includes the following steps:

In step 1301, a logging while drilling device (preferably, for example, an electromagnetic wave propagation resistivity forward detecting device shown in FIG. 1) is placed in a high resistance target layer at a certain depth position, while the logging device continues to drill. The logging device performs continuous detection with a direction of detection that coincides with the direction of axial movement of the logging device (preferably the electromagnetic wave propagation resistivity forward detecting device shown in the figure).

In step 1302, two consecutive measurement points (e.g., a first measurement point and a second measurement point) are selected, and at least two consecutive measurements are taken at each measurement point.

In step 1303, if the amplitude ratio of the induced electromotive force between the first receiving line and the second receiving line in the axial direction of the logging device in the at least two consecutive measurements at the first measuring point is changed The quantity Δ^" and the phase difference change amount A PSD are in their respective predetermined threshold ranges (for example, the predetermined amplitude ratio variation amount threshold value may be 0-0.03 dB or other predetermined range, and the predetermined phase difference variation amount threshold value range is 0° Within -0. 1° or other predetermined range), the first measurement point is saved as a select point of the first homogeneous formation.

In step 1304, if the amplitude ratio of the induced electromotive force between the first receiving line and the second receiving line in the axial direction of the logging device in the at least two consecutive measurements at the second measuring point is changed The quantity ^ ¹ " and the phase difference variation A PSD are both within the respective predetermined threshold ranges, and the second measurement point is saved as a second homogeneous formation optional point.

If it is determined in steps 1303 and 1304 that two homogeneous formation selectable points satisfying the above conditions are not found, then return to step 1302 to continue the measurement while drilling, and so on. Until you find a selection of two homogeneous formations that meet the criteria.

After the first and second homogeneous formation optional points are found via steps 1303 and 1304, in step 1305, the first received line measured at the first and second homogeneous formation optional points An average of amplitude ratios of induced electromotive forces between the 接收 and the second receiving line ( (ie, an average of a plurality of amplitude ratios obtained for each measurement performed at the selectable points of the two homogeneous formations) or The average of the root mean square and phase difference (the average of multiple phase differences obtained from each measurement at two selectable points in the homogeneous formation) or the root mean square as the formation of the layer with the measured high resistance The magnitude of the induced signal of the logging device corresponding to the resistivity is greater than the base value "0" and the phase difference base value PSDQ.

Next, in step 1306, the standard value of the formation resistivity of the measured high resistance target layer is determined and stored, that is, the above amplitude ratio base value corresponding to the formation resistivity of the measured high resistance target layer is ^0. And the phase difference base value Α3⁄4) θ is compared with the corresponding predetermined eigenvalues of the various formations, and the type of ground and phase difference standard values closest to the base value and the phase difference base value are selected and stored. The amplitude is greater than the standard value and the phase difference standard value.

Optionally, in step 1307, the exit threshold of the measured high resistance target layer is set according to an amplitude ratio standard value and a phase difference standard value corresponding to the formation resistivity of the measured high resistance target layer. Specifically, when the logging device is close to the low resistance boundary, the amplitude ratio and the phase difference of the induced electromotive force between the first receiving coil and the second receiving coil in the axial direction of the logging device are caused. The closer the logging device is to the low resistance boundary, the measured amplitude ratio is the variation (ie, the difference) with respect to the standard value of the amplitude ratio, and the variation of the measured phase difference with respect to the standard value of the phase difference (ie, The larger the difference), when the amplitude ratio change and the phase difference change amount reach or exceed a predetermined value, it is generally considered that a low-resistance formation appears in front of the logging device. The predetermined value is the exit threshold as described herein. It should be noted that the ejecting threshold can be set to different predetermined values according to the characteristics and measurement conditions of the actual measured stratum for the different measured strata by the person skilled in the art, generally through the current measured stratum and the front stratum. The resistivity contrast is determined. Preferably, the exit threshold can be set to an amplitude ratio of 1% of the standard value or the phase difference standard value regardless of the resistivity contrast of the two layers of the current measured formation and the front formation. 30%; Further preferably, when the resistivity contrast is 1 /10, the layer threshold may preferably be set to 10% of the amplitude ratio standard value or phase difference standard value. The manner of determining the above-mentioned layering threshold and the numerical values are merely exemplary, and should not constitute a limitation on the scope of the present invention. As shown, in step 1308, the next measurement point is continued, at least two measurements are taken at the next measurement point, and the first receive coil and the second along the axial direction of the logging device at the measurement point are calculated. The amplitude ratio change amount tt and the phase difference change amount Δ PSD of the induced electromotive force between the receiving coils.

In step 1309, it is determined whether the amplitude ratio change amount Δ^" and the phase difference change amount A PSD calculated in step 1308 are greater than the exit threshold; if greater, it is determined that the front of the logging device is a low-resistance formation; If not greater than, the current amplitude ratio change amount "and the phase difference change amount A PSD is stored, and then it is determined whether the predetermined nth measurement point has been reached. If not, then return to step 1308 to continue the selection and amplitude of the next measurement point. The calculation of the ratio change amount and the phase difference change amount A PSD , if it is the predetermined nth measurement point, proceeds to step 1310. It should be noted that the η here is selected by the technician according to the actual situation according to the characteristics of the formation and the measured speed. For example, if it is for a softer stratum (such as sandstone in the Bohai area), the value of η It can be relatively small, and for harder formations (such as shale), the value of η can be relatively large. Generally, for ordinary formations, η is preferably 20-30, but the invention is absolutely Without being limited thereto, it may be other suitable values.

In step 1310, the amplitude ratio change trend and the phase difference change trend are determined according to the amplitude ratio change amount and the phase difference change amount A PSD at the respective measurement points stored before; if the change trend is from the third measurement point To the ηth measurement point, the amplitude ratio change amount and the phase difference change amount are kept increasing in the same direction (that is, the amplitude ratio change amount and the phase difference change amount at the m+1 measurement point are respectively higher than the mth measurement point The amplitude ratio change amount and the phase difference change amount are large, and the m=l, 2, . . . , nl) determines that the front of the logging device is a low-resistance formation;

Otherwise, if the trend of change is generally in the same direction, it is also determined that the front of the logging device is a low-resistance formation; the overall same-directional increase described herein means: although there is an ups and downs in the middle of the change trend (ie It is said that the amplitude ratio change amount and the phase difference change amount at a certain measurement point are reduced with respect to the amplitude ratio change amount and the phase difference change amount at the previous measurement point), but for example, at least 70% of the measurement points The trend of increasing in the same direction is maintained, and the percentage is also preset by the technician according to the actual measurement situation. The 70% is merely exemplary and does not constitute a limitation on the scope of protection of the present invention.

If the trend of change is neither increasing in the same direction nor increasing in the same direction, then the decision is made. There is no low-resistance formation in front of the logging device.

According to another preferred embodiment of the present invention, in the base value determining process described in the above step 1305, the formation of the first and second homogeneous layer selectable points may be calculated by the magnetic dipole source dyadic Green's function. Resistivity, amplitude ratio, and phase difference. By way of example, Figures 9-12 illustrate several exemplary eigenvalue comparison tables for measuring formation resistivity versus amplitude ratio and phase difference, the corresponding physical quantities in the eigenvalue comparison table passing through the magnetic dipole source and The vector green function is calculated. 9 is a comparison of various measured formation resistivity and amplitude ratios and phase difference converted eigenvalues of the logging device antenna for T2-R1 -R2 at a transmission frequency of 2 MHz according to a preferred embodiment of the present invention. Figure 10 shows a comparison of various measured formation resistivity and amplitude ratios and phase difference converted eigenvalues of a logging device antenna for T2-R1 - R2 at a transmission frequency of 400 kHz in accordance with a preferred embodiment of the present invention. Figure 1 1 shows various measured formation resistivity and amplitude ratios and phase difference converted eigenvalues of a logging device antenna for T 1 -R1 -R2 at a transmission frequency of 2 MHz in accordance with a preferred embodiment of the present invention. Figure 12 shows the eigenvalues of various measured formation resistivity and amplitude ratios and phase difference conversions of the logging device antenna for T1 - R1 - R2 at a transmission frequency of 400 kHz in accordance with a preferred embodiment of the present invention. Comparison table.

Moreover, in accordance with still another preferred embodiment of the present invention, the logging method preferably further comprises calculating a front low resistance formation to a logging device using a Sommerfeld integral (eg, an electromagnetic wave propagation resistivity forward detecting device in accordance with the present invention) the distance.

Figure 2 of the present application shows a two-layer formation model diagram preferably used in a logging method for forward detection of an electromagnetic wave propagation resistivity forward detecting device in accordance with a preferred embodiment of the present invention.

As shown in Fig. 2, each reference numeral denotes: formation 1; 2: formation 2; 3: layer interface between formation 1 and formation 2; 4: electromagnetic wave propagation resistivity forward detection device core axis; 5: Electromagnetic wave propagation resistivity measurement point of the forward detecting device; 6: Electromagnetic wave propagation resistivity The distance from the measuring point of the forward detecting device to the layer interface 3 between the ground layer 1 and the ground layer 2; 7: The receiving antenna R1 with a mounting angle of zero; 8: receiving antenna R2 with a mounting angle of preferably zero degrees; 9: receiving antenna R3 with a mounting angle of preferably 45°; 10: receiving antenna R4 with a mounting angle of preferably -45°; 1 1 , a transmitting antenna with a mounting angle of preferably zero Tl. According to the two-layer formation model, the electromagnetic wave propagation resistivity forward detecting device is disposed in the formation 1 and perpendicular to the interface of the formation 1 and the formation 2, and can be obtained by changing the distance between the formation interface 3 and the center point of the device. Amplitude attenuation and phase shift changes in the formation with resistivity contrast. 3 to 8 illustrate amplitude attenuation responses or phase shifts of different transmit-receive antenna pairs in different resistivity contrast formations when different frequencies are employed, in accordance with a preferred embodiment of the present invention. Respond to changes in the position of the interface with the ground plane. The abscissas in Figures 3-8 represent the distance from the formation interface 3 to the center point of the device, and the ordinate indicates the response of the coil system in the two formations and in the homogeneous formation in which the electrical parameters of the formation 1 are resistivity. Difference.

It is assumed that the amplitude-attenuation threshold of the electromagnetic wave propagation resistivity forward detecting device according to the preferred embodiment of the present invention is 0.02 dB, and the phase shift threshold is 0. Γ (shown by the horizontal line in FIGS. 3-8) 3 to 8 can obtain the vertical depth of detection of each pair of antennas in the detection device in different resistivity contrast formations.

For example, in a 10/1 resistivity contrast formation, if the frequency of the transmit-receive antenna pair is 2 MHz, the amplitude attenuation of the 16/22 in. (ie inches) antenna pair and the vertical depth of the phase shift are 41 in. And 26 in., 32/38ιη. The amplitude attenuation of the antenna pair and the vertical depth of the phase shift are 56 in. and 37 in. respectively; if the frequency of the transmit-receive antenna pair is 400 kHz, the 16/22 in. antenna pair The amplitudes of the amplitude attenuation and phase shift are 43 in. and 35 in., respectively, and the 32/38 in. antenna pair amplitude attenuation and phase displacement vertical detection depth are 67 in. and 48 in., respectively.

In the 50/1 resistivity contrast formation, if the frequency is 2MHz, the amplitude attenuation of the 16/22in. antenna pair and the vertical depth of the phase shift are 55 in. and 35 in., 32/38 in. The vertical attenuation depths of the amplitude attenuation and phase shift are 77 in. and 46 in. respectively; if the frequency is 400 kHz, the amplitude attenuation of the antenna pair and the vertical displacement of the phase shift ^! The amplitudes of amplitude attenuation and phase shift of the antenna pairs of 49 in. and 44 in., 32/38 in. respectively are 82 in. and 62 ηη.

In a 200/1 resistivity contrast formation, if the frequency is 2 MHz, the amplitude attenuation of the 16/22 in. antenna pair and the vertical depth of phase shift are 61 in. and 43 in., 32/38 in. antenna, respectively. The vertical depths of amplitude attenuation and phase shift are 92 in. and 57 in. respectively; if the frequency is 400 kHz, the amplitude attenuation of the 16/22 in. antenna pair and the vertical depth of phase shift are 50 respectively. In. and 47 in. , 32/38 in. The amplitude attenuation of the antenna pair and the vertical depth of phase shift are 87 in. and 71 in., respectively.

It can be seen from Fig. 3 to Fig. 8 that as the resistivity contrast of the formation increases, the amplitude attenuation response or the phase displacement response changes more gently with the position of the formation interface. As the formation resistivity contrast and the antenna pitch increase, the vertical depth of the detection device increases. In the same resistivity contrast formation, the vertical detection depth of the amplitude attenuation curve of the same antenna is greater than the vertical detection depth of the phase displacement curve.

The presence of the formation interface or the oil-water interface may be determined by measuring the amplitude attenuation or the phase shift signal in real time by the logging while drilling device disposed in the drilling device according to the present invention during the forward drilling of the drilling device. This controls the drill to travel through the best position in the reservoir. If the LWD tool does not exhibit the above-mentioned amplitude attenuation or phase shift signal change during the drilling of the drilling device, that is, the amplitude attenuation of the LWD device or the reading of the phase shift signal is constant. This means that there is no low-resistance formation. If the amplitude attenuation or phase shift signal reading changes during the forward drilling of the drilling unit, it means that there is a low-resistance formation in front of the drilling unit, and the wellbore trajectory needs to be adjusted in time to avoid drilling into the low-resistance formation, thus The drilling unit is always located in the high-resistance oil-bearing purpose interval, thereby achieving pre-drilling prediction and precise geosteering of the formation interface.

It should be noted that although the present invention has described preferred embodiments with reference to oil drilling, the logging apparatus and logging method of the present invention are not limited to the field of oil drilling, but are also widely applicable to other drilling industries such as coal mining and mining. .

Hereinafter, the present specification will further describe a data processing apparatus for implementing the logging method according to a preferred embodiment of the present invention.

As shown in FIG. 14, the data processing apparatus according to the present invention preferably includes: first and second measurement point selecting means 1400, first amplitude ratio change amount and phase difference change amount calculating means 1401, second amplitude ratio change amount and Phase difference variation calculation device 1402, first homogeneous formation optional point determination device 1403, second homogeneous formation optional point determination device 1404, storage device 1405, base value determination device 1406, standard value determination device 1407, and egress layer Threshold setting means 1408, third-nth measurement point selection and calculation means 1409 and low resistance formation determination means 1410.

The first and second measurement point selection devices 1400 select two consecutive measurement points (ie, a first measurement point and a second measurement point), and instruct the logging device to perform at least two at each selected measurement point. Sub-continuous measurement.

The first and second measurement point selecting means 1400 are coupled to the first amplitude ratio change amount and phase difference change amount calculating means 1401 and the second amplitude ratio change amount and phase difference change amount calculating means 1402, respectively.

The first amplitude ratio change amount and phase difference change amount calculation means 1401 is configured to calculate at the first measurement point selected by the first and second measurement point selection means 1400, An amplitude ratio change amount A^t and a phase difference change amount A PSD of the induced electromotive force between the first receiving coil and the second receiving coil in the axial direction of the logging device in at least two consecutive measurements; the second amplitude ratio The variation and phase difference variation calculation device 1402 is configured to calculate the axial direction along the logging device at the second measurement point selected by the first and second measurement point selection devices 1400 in the at least two consecutive measurements An amplitude ratio change amount Δί" of the induced electromotive force between the first receiving line 圏 and the second receiving line 方向 and a phase difference change amount A PSD; the first homogeneous formation selectable point determining device 1403 is coupled to the The first amplitude ratio change amount and phase difference change amount calculating means 1401 is configured to determine the sensing between the first receiving line 圏 and the second receiving line 轴向 in the axial direction of the logging device at the first measuring point The amplitude ratio change amount and the phase difference change amount A PSD of the electromotive force are within their respective predetermined threshold values, and if so, the first measurement point is stored as the first homogeneous formation optional point in the storage device 1405. If no, the indication office The first and second measuring point selecting means 1400 reselect the measuring point. Preferably, the predetermined amplitude ratio change amount threshold value range may be 0-0.03 dB or other predetermined range, and the predetermined phase difference change amount threshold value range is 0°-0.1 ° or other predetermined range.

The second homogeneous formation selectable point determining device 1404 is coupled to the second amplitude ratio change amount and phase difference change amount calculating means 1402, and is configured to determine the axial direction of the logging device at the second measuring point Whether the amplitude ratio change amount and the phase difference change amount A PSD of the induced electromotive force between the first receiving line 圏 and the second receiving coil are within their respective predetermined threshold ranges, and if so, the second measuring point is taken as the first The optional points of the two homogeneous formations are stored in the storage device 1405. If not, the first and second measurement point selection means 1400 are instructed to reselect the measurement point.

The base value determining device 1406 is coupled to the storage device 1405 and configured to determine an amplitude ratio of the sensing signal of the logging device corresponding to the formation resistivity of the measured high resistance target layer to a base value of 0 and a phase difference base value 3⁄4£»o. According to a preferred embodiment, the base value determining means 1406 senses the induced electromotive force between the first receiving coil and the second receiving coil at the first and second homogeneous formation selectable points stored in the storage means 1405. The average of the amplitude ratios (average of multiple amplitude ratios for each measurement made at the optional points of the two homogeneous formations) or the average of the root mean square and phase difference (in two homogeneous formations) The average value of the plurality of phase differences obtained by each measurement at the optional point or the root mean square is respectively used as the amplitude ratio base value ^"0 and the phase difference base value corresponding to the formation resistivity of the measured high resistance target layer. PSDQ.

Preferably, the base value determining means 1406 is calculated by a magnetic dipole source dyadic Green's function The formation resistivity, the amplitude ratio and the phase difference of the selectable points of the first and second homogeneous formations are calculated. It is to be noted that the base value determining means 1406 may also use other existing functions or algorithms to calculate the formation resistivity, amplitude ratio and phase difference of the selectable points of the first and second homogeneous formations.

The standard value determining means 1407 is coupled to the base value determining means 1406 and the storage means 1405 and is used to determine and store a standard value of the formation resistivity of the measured high resistance target layer. According to a preferred embodiment, the standard value determining means 1407 is adapted to compare the amplitude ratio base value and phase difference base value corresponding to the formation resistivity of the measured high resistance target layer with corresponding predetermined eigenvalues of various formations. Selecting an eigenvalue of the type of the layer closest to the base value and the phase difference base value as the amplitude ratio standard value and phase difference standard value corresponding to the formation resistivity of the measured high resistance target layer And storing the amplitude in the storage device 1405 in comparison with the standard value and the phase difference standard value.

The exit threshold setting means 1408 is coupled to the standard value determining means 1407 and the storage means 1405 and is used to set the exit threshold of the measured high resistance target layer. According to a preferred embodiment, the exit layer threshold setting means 1408 sets the output of the measured high resistance target layer according to an amplitude ratio standard value and a phase difference standard value corresponding to the formation resistivity of the measured high resistance target layer. The layer threshold is then preferably stored in the storage device 1405.

Specifically, when the logging device is close to the low resistance boundary, the amplitude ratio and the phase difference of the induced electromotive force between the first receiving line 圏 and the second receiving line 轴向 in the axial direction of the logging device are caused. The closer the logging device is to the low resistance boundary, the measured amplitude ratio is the variation amount (ie, the difference) with respect to the standard value of the amplitude ratio, and the variation of the measured phase difference with respect to the standard value of the phase difference ( The larger the difference, the greater the resistance, the change in the amount of change and the phase difference to or above a predetermined value is generally considered to occur in the front of the logging device. The predetermined value is the exit threshold as described herein. As described above, the threshold of the egress layer can be set to different predetermined values according to the characteristics and measurement conditions of the actual measurement stratum for the different measurement strata by the person skilled in the art, generally through the two layers of the current measured stratum and the front stratum. The resistivity contrast is determined. Preferably, the exit threshold can be set to an amplitude ratio of 1% of the standard value or the phase difference standard value regardless of the resistivity contrast of the two layers of the current measured formation and the front formation. 30%; Further preferably, when the resistivity contrast is 1 /10, the layer threshold may preferably be set to 10% of the amplitude ratio standard value or phase difference standard value. The manner of determining the above-mentioned layering threshold and the numerical values are merely exemplary, and should not constitute a limitation on the scope of the present invention. Personnel can choose the appropriate value by other means according to the actual situation.

The third-nth measurement point selection and calculation device 1409 is configured to continue to select the next measurement point, perform at least two measurements at the next measurement point, and calculate the first direction along the axial direction of the logging device at the measurement point. The amplitude ratio change amount and the phase difference change amount Δ PSD of the induced electromotive force between a receiving line 圏 and the second receiving line 。.

The low resistance formation determining means 1410 is coupled to the storage means 1405, the exit threshold setting means 1408 and the third - nth measuring point selecting and calculating means 1409, respectively.

According to a preferred embodiment, the low-resistance formation determining device 1410 includes a layering threshold determining unit 14101 for determining a change in the amplitude ratio of the current measuring point calculated in the third-nth measuring point selection and computing device 1409. Whether the quantity ^ and the phase difference change amount A PSD is greater than the exit threshold; if it is greater, it is determined that the front of the logging device is a low-resistance formation; if not, the amplitude ratio of the current measurement point is preferably changed and phase The difference variation A PSD is stored in the storage device 1405.

According to another preferred embodiment, the low-resistance formation determining means 1410 further includes a measuring point number determining unit 14102 and an amplitude ratio and phase difference changing tendency determining unit 14103.

The measurement point number determining unit 14102 is configured to determine whether the current measurement point has reached the predetermined time when the out-of-layer threshold value determining unit 14101 determines that the amplitude ratio change amount and the phase difference change amount A PSD of the current measurement point are not greater than the exit threshold value. The nth measurement point, if not, instructs the third-nth measurement point selection and calculation device 1409 to continue the selection of the next measurement point and the amplitude ratio change amount Δ^" and the phase difference variation A PSD If the current measurement point is the predetermined nth measurement point, the indication amplitude ratio and phase difference change trend determining unit 14103 is based on the previously stored measurement points (ie, 3, 4, 5... η The amplitude ratio change amount Δ^" and the phase difference change amount A PSD at the measurement point) determine the amplitude ratio change tendency and the phase difference change tendency.

As mentioned above, η here is selected by the technician according to the actual conditions of the formation according to the characteristics of the formation and the measured speed. For example, if for a softer formation (such as sandstone in the Bohai area), the value of η can be Relatively small, and for harder formations (such as shale), the value of η can be relatively large. Generally, for ordinary formations, η is preferably 20-30, but the present invention never Limits to this, it can be other suitable values.

According to still another preferred embodiment, the low-resistance formation determining device 1410 further includes a co-directional incremental change trend determining unit 14104, wherein the co-directional incremental change trend determining unit 14104 is configured to determine that the amplitude ratio and the phase difference change trend are determined. The change determined by unit 14103 Whether the trend is from the third measurement point to the nth measurement point, the amplitude ratio change amount and the phase difference change amount keep increasing in the same direction (that is, the amplitude ratio change amount and phase difference change at the m+1 measurement point) The amount is larger than the amplitude ratio change amount and the phase difference change amount at the mth measurement point, respectively, the m=l, 2, . . . , nl), and if yes, the front of the logging device is determined to be low Resist the formation.

According to still another preferred embodiment, the low-resistance formation determining device 1410 further includes an overall in-situ incremental change trend determining unit 14105, configured to determine whether the change trend is the same when the determination result of the determining unit 14104 is negative. The direction is incremented, and if so, it is determined that the front of the logging device is a low resistance formation; if not, it is determined that no low resistance formation is present in front of the logging device. As previously mentioned, the overall in-situ increment here means: although there is an ups and downs in the middle of the trend (that is, the amplitude ratio change and the phase difference change at a certain measurement point are relative to the previous measurement point). The amplitude is smaller than the amount of change and the amount of phase difference change), but for example, at least 70% of the measurement points maintain a trend of increasing in the same direction, which is also preset by the technician based on the actual measurement. The 70% is merely exemplary and does not constitute a limitation of the scope of the present invention.

Please note that the preferred embodiment can be implemented in hardware, software, firmware or a combination thereof. In various embodiments(s), the device components are implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in some embodiments, the device components can be implemented with any of the following techniques or combinations thereof well known in the art: having a logic gate for implementing logic functions on data signals (one or Multiple) discrete logic circuits, application specific integrated circuits (ASICs) with appropriate combinational logic gates, programmable gate array(s) (PGA), field programmable gate arrays (FPGAs), and more.

A software component can include an ordered list of executable instructions for implementing logical functions, which can be embodied in any computer readable medium for use by or in connection with an instruction execution system, apparatus, or device, the instruction execution system A device or device, such as a computer-based system, a system containing a processor, or other system capable of acquiring instructions from an instruction execution system, apparatus, or device and executing the instructions. Further, the scope of the present disclosure includes the functionality of one or more embodiments embodied in logic embodied in a hardware or software constructed medium.

The foregoing disclosure of the embodiments of the present disclosure has been presented for purposes of illustration and description. Many variations and modifications of the embodiments described herein will be apparent to those skilled in the art. Please note that the above examples are not intended to be limiting. Additional embodiments of devices, methods and apparatus that can include many of the above features are also contemplated. Other devices, methods, devices, features, and advantages of the present disclosure will be apparent to those skilled in the <RTIgt; All such other devices, methods, devices, features, and advantages are intended to be included within the scope of the present invention. Solution, otherwise conditional languages such as "can", "may", "may," or "may" are generally intended to convey that certain embodiments may include, but do not necessarily include certain features, components, and/or steps. Therefore, such conditional language is not intended to imply that any one or more embodiments are required to include features, elements and/or steps.

Any processing description or block in the flowcharts should be understood to represent a portion of the code that includes one or more executable instructions for implementing a particular logical function or step in the process, in which the The order of the arguments is to perform the functions: Included substantially simultaneously or in reverse order, depending on the function involved, as will be understood by a skilled person in the field of the present disclosure.

Claims

Rights request

A logging method comprising:

(d) determining, according to the amplitude ratio base value and the phase difference base value, a magnitude ratio standard value and a phase difference standard value corresponding to the formation resistivity of the measured high resistance target layer;

(g) determining whether the magnitude ratio change and/or the phase difference variation of the induced electromotive force between the pair of receiving turns of the logging device at the current measurement point is greater than the exit threshold;

(h) If the answer in step (g) is YES, then it is determined that a low-resistance formation appears in front of the logging device.

2. The logging method according to claim 1, wherein the step (b) further comprises: if any one of the selected measurement points cannot be used as a homogeneous formation selectable point, returning to step (a) Reselect the continuous measurement points.

3. The logging method according to claim 1, wherein the step (b) further comprises:

If the amplitude ratio change amount and the phase difference change amount of the induced electromotive force between one pair of receiving coils of the logging device at one of the selected measuring points are within their respective predetermined threshold values, the measurement is taken Points are optional points for homogeneous formations.

4. The logging method according to claim 1, wherein the step (c) further comprises:

The mean value or the root mean square and the root mean square of the magnitude of the induced electromotive force between the pair of receiving turns measured at the selectable points of the two homogeneous formations, respectively, or the root mean square As the amplitude ratio base value and phase difference base value.

The logging method according to claim 4, wherein in the step (c), the magnetic dipole source dyadic Green's function is used to calculate the selectable points of the two homogeneous formations. Corresponding formation resistivity, amplitude ratio and/or phase difference.

The logging method according to claim 1, wherein the step (d) further comprises:

Comparing the amplitude to the base value and the phase difference base value to predetermined eigenvalues of the predetermined various types of formations, and selecting the type of the stratum that is closest to the base value and the phase difference base value The eigenvalue is taken as the amplitude ratio standard value and phase difference standard value corresponding to the formation resistivity of the measured high resistance target layer.

The logging method according to claim 1, wherein the logging method further comprises:

Step (i), when the judgment result of the step (g) is negative, storing the amplitude ratio change amount and the phase difference change amount at the current measurement point, determining whether the predetermined nth measurement point is reached, and if not, returning to the step (f ) , wherein the n is a natural number greater than 4.

The logging method according to claim 7, wherein the logging method further comprises:

Step (j), when the step (i) determines that the current measurement point is the predetermined nth measurement point, the amplitude is determined according to the amplitude ratio change amount and the phase difference change amount at each of the previously stored measurement points. The trend of change trend and phase difference.

The logging method according to claim 8, wherein the logging method further comprises:

Step (k), if the change trend is from the third measurement point to the nth measurement point, the amplitude ratio change amount and the phase difference change amount keep increasing in the same direction or in the same direction, determining the measurement A low-resistance formation appears in front of the well device; otherwise, if neither the same direction nor the general same direction increases, then it is determined that there is no low-resistance formation in front of the logging device.

10. A data processing apparatus, characterized in that the data processing apparatus comprises: a homogeneous layer selectable point determining device (1403, 1404) for determining whether two consecutive measuring points currently selected by the logging device are average Can be used as an optional point for homogeneous formations;

a base value determining device (1406) for determining, based on the two selectable points of the homogeneous formation layer, if the determination result of the homogeneous formation point selectable device (1403, 1404) is YES The amplitude of the induced signal of the logging device corresponding to the formation resistivity of the measured high resistance target layer is greater than the base value and the phase difference base value; a standard value determining device (1407) for determining an amplitude ratio standard value and a phase difference standard value corresponding to a formation resistivity of the measured high resistance target layer according to the amplitude ratio base value and the phase difference base value;

An egress threshold setting device (1408) configured to set an eject threshold of the measured high-resistance target layer according to the amplitude ratio standard value and a phase difference standard value;

a third-th nth measuring point selection and calculating device (1409) for continuously selecting the next measuring point for at least two measurements, and calculating a pair of receiving lines of the logging device at the currently selected measuring point The magnitude of the induced electromotive force between the amount of change and the amount of change in phase difference;

The data processing device according to claim 10, wherein the homogeneous layer selectable point determining means (1403, 1404) is configured to determine at the selected measuring point, in the logging device Whether the magnitude of the induced electromotive force between the pair of receiving coils and the amount of change in the phase difference is within their respective predetermined threshold ranges, and if so, the measuring points participating in the determination are used as the homogeneous layer optional points .

12. The data processing apparatus according to claim 10, wherein said homogeneous layer selectable point determining means (1403, 1404) determines that any one of the selected measuring points cannot be used as a homogeneous layer selectable point, It then instructs the logging device to reselect the continuous measurement point.

13. The data processing apparatus according to claim 10, wherein: said base value determining means (1406) is further configured to: said said measured at said select points of said two homogeneous formations The average value or the root mean square or the root mean square of the amplitude ratio of the induced electromotive force between the pair of receiving coil turns as the amplitude ratio base value and the phase difference base value, respectively.

14. The data processing apparatus according to claim 10, wherein the standard value determining means (1407) is further configured to: base the amplitude ratio base value and the phase difference base value with a predetermined various types of strata Comparing the corresponding eigenvalues, selecting the eigenvalue of the type of the layer closest to the base value and the phase difference base value as the formation corresponding to the formation resistivity of the measured high resistance target layer The amplitude is greater than the standard value and the phase difference standard value.

15. The data processing device according to claim 10, wherein said low resistance The formation determining device (1410) further includes a measuring point number determining unit (14102) and an amplitude ratio and phase difference change trend determining unit (14103);

The measurement point number determining unit (14102) is configured to determine the current measurement point when the exit layer threshold determining unit (14101) determines that the amplitude ratio change amount and the phase difference change amount of the current measurement point are not greater than the exit layer threshold value. Whether the predetermined nth measurement point has been reached; if not, instructing the third-nth measurement point selection and calculation device (1409) to continue the selection of the next measurement point and the amplitude ratio change amount and the phase difference change amount On the other hand, if the current measurement point is the predetermined nth measurement point, the amplitude ratio and phase difference change trend determining unit (14103) is indicated to vary the amplitude ratio and the phase difference according to the previously stored measurement points. The amount of change is used to determine the trend of the amplitude ratio change trend and the phase difference.

The data processing device according to claim 15, wherein the low-resistance formation determining means (1410) further comprises a co-directional incremental change trend determining unit (14104), and the co-directional incremental change trend determining unit ( 14104) configured to determine whether the change trend determined by the amplitude ratio and phase difference change trend determining unit (14103) is from a third measurement point to an nth measurement point, the amplitude ratio change amount and phase difference The amount of change remains increasing in the same direction, and if so, it is determined that the front of the logging device is a low resistance formation.

17. The data processing apparatus according to claim 16, wherein the low resistance formation determining means (1410) further comprises an overall co-directional incremental change trend determining unit

(14105), configured to determine whether the change trend is generally in the same direction when the determination result of the determining unit (14104) is negative, and if yes, determine that the front of the logging device is a low-resistance formation; Otherwise, it is determined that there is no low resistance formation in front of the logging device.

18. A logging device, characterized in that the logging device comprises a drill collar body (12) and an antenna array, wherein the antenna array comprises at least one pair of transmitting antennas and receiving antennas, the transmitting antenna and the receiving antenna Used to generate a forward probing depth curve.

19. The logging device according to claim 18, wherein the antenna array comprises four transmitting antennas T1 (11), T2 (14), T3 (13) and T4 (15), and four receiving Antennas R1 ( 7 ) , R2 ( 8 ) , R3 ( 9 ) and R4 ( 10 ).

The logging device according to claim 19, wherein the antenna array is arranged from the tail end of the drill collar body (12) to the drill bit end: a receiving antenna R3, a transmitting antenna T3, Transmitting antenna Tl, receiving antenna Rl, receiving antenna R2, transmitting day a line T2, a transmitting antenna Τ4, and a receiving antenna R4; a midpoint between the receiving antennas R1 and R2 is a measuring point, and the transmitting antennas T1 and Τ2, Τ3 and Τ4 are respectively symmetrically mounted with the measuring point as a center; The mounting angles of the receiving antennas R 1 and R2 are substantially zero degrees; the receiving antennas R3 and R4 are disposed at both ends of the drill collar body ( 12 ) with the measuring points as a center of symmetry, and the receiving The mounting angles of the antennas R3 and R4 are set to about 45° and about -45°, respectively.